A. Field of the Invention
This invention relates to an operation device for endoscopes which includes an insertion section containing a bending tube and, in particular, an operation device for endoscopes having a plurality of operation knobs for operating an operation section, such as a bending tube.
B. Description of the Prior Art
An operation section of a typical endoscope contains a bending operation device for bending a bending tube of an insertion section of the endoscope. This type of a bending operation device is disclosed, for example, in Japanese Patent Disclosure (KOKAI) No. 60-246728. In the disclosed bending operation device, a plurality of operation knobs are mounted around a common center axis and respective operation knobs are sequentially mounted one over another on the outer surface of an operation body. The knob for restricting the guiding direction of a treatment instrument inserted through the channel of the endoscope insertion section and the knob for locking a bending operation knob of a bending tube are sequentially mounted on the operation body in which case the bending operation knob is connected to the outside of the restricting knob and locking knob.
The operator has to operate the respective knobs with fingers of the same hand which grips the operation body of the endoscope. The reason is that it is necessary for the operator to use his other hand to move the treatment instrument, which has been inserted through the channel of the endoscope, back and forth. It is also necessary for the operator to perform other operations, with his free hand, such as the operation for inserting the insertion section of the endoscope into a body cavity.
In the conventional operation device of an endoscope, when the operator grips the operation section of the endoscope with his hand, the bending operation knob is located at such a distance from the gripping hand that it is hard for the operator to readily operate the neighboring associated knob with a finger of the same hand.